From [1]:
pep257 yields some error which apparently cause flake8 2.2.3 to stall
completely waiting for some input.
An upstream issue [2]
[1]: https://gerrit.wikimedia.org/r/157291
[2]: https://bitbucket.org/tarek/flake8/issue/167/flake8-223-stall-with-multiprocessing
Version: wmf-deployment
Severity: normal